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`SIPECIFICA'J'JIGN forming part of Letters Patent No. 605,486, dated J'une 14, 1898. Application mea october 22,1897. serial No. 656,063.(No'mdetj l To all whom/ t mengpaneel/'n.-

Be it known that I,' HERMAN GEORGE KOT TEN, a citizenof the UnitedStates, residing at New York,.in the county, of NewYork, StateA of NewYork, have invented anewand useful Improvement in Pneumatic'Tools,whichim-V provement is fully set forth inthefollowing specification andaccompanying drawings.

My invention consists of an improved construction of pneumatic tool inwhich a solid piston-hammer is employed; and it consists especially in anovel construction of exhaustports which are located in thechisel-bushing and communicate with the main exhaust, in combinationwith other ports and passages so arranged relatively toeachother thatthe hammer has a comparatively slowmovement away from the chisel or toolemployed, but

has an exceedingly rapid or accelerated move; ment in the direction ofsaid chisel.

It further consists of novel details of construction, all as will behereinafter fully set forth, and particularly pointed out in the claims.

Figures 1 and represent longitudinalsec tional views of a pneumatic.tool embodying my invention, showing the different positions whichthepiston-hainmer thereof assumes at the commencement andenfdL of itsstroke, respectively. Fig. 3 representsla section on line. fr Fig. 1,yshowing the' relative positions of the. various ports.V and .passagesin'the cylin' der or casing of the tool.

Similar numerals and letters of reference indicate corresponding partsin the figures.

`Referring to the drawings, 1. designates a pneumatic tool, the sameconsisting of a suitable barrel or cylinder which has the inletport lXtherein, said port communicating with the passages 2 and 3, whichdischarge into the vmain inlet-port 4t, in proximity to which is locatedan annulargroove or supply-chamber 5, whichextends around the interiorperiphery of the' cylinder, whereby no side pressure upon thepiston-hammer A can exist and the same can reciprocate freely in eitherdirection.;AM

6 designates an inlet-port communicating with the interior of thecylinder a short distance at one side of or to the right of the chamber5, said port 6 leading into the passage 7 i andportS, which .opens intothe 'cylinder near the chisel end of the hammer, in the present instanceat appoint adjacent to the termination of thechisel-bushing 18.

j 1'1." designates a plurality of `exhaust-ports'lwhich'passfthrough'the chisel-bu'shin g 18 and communicate Vby theannular passage l2 with the main exhaust; passage 10, which dischargesinto the atmosphere through the ports 13, said exhaust-port 11 beingcontrolled by the nose or projecting striking-face A of thepiston-hammer AX,which latter consists of the enlarged portions B D F,which are connected by the grooves or reduced portions or necks O andE,said nose A entering the bore 18X of the chisel-bushing 1 8 when saidhammer is near'the end of its stroke, it being noted that said nosemoves entirely out of said bore 18 when near the other end of itsstroke.

' 14 designates aninlet-port located a slight distance to one side of orto the left of the m-ain inlet-port 4 and communicating with the passage15, which admits the motive fluid to the interior of the cylinderthrough the port 16,'lo'ca'ted' at the right-hand portion thereofl L i I17 designatesa chisel or tool whichis held inthe chisel=bu"shing.18,said bushing being heldin position by means of a latch-pin 19 r` anyother suitable fastening device."

i' .The operation isas follows :The fluid-supplypipe (not shown)f is...connected with the inlet 1X of the cylinder, and the motive fluidentering the cylinder passes to the main inlet-port 4: and the annularsupply-chamber 5. In Fig. 1 the piston-hammer A is shown at or near itsextreme downward or left-hand position at the point where it contactswith the chisel or `tool 17, the chamber 5 being now in communicationvwith the port 6 through the medium of the neck or groove E of saidhammer. The motive fluid passes through hammer is in the position seenin Fig. 1, the exhaust-port 9, which is substantially onefourth theareaof port l1, is open and allows IOO the pressure within the cylinderupon theback or right-hand end of said hammer to escape through thepassage 10 and port 13 into the atmosphere. The motive liuid afterpassing through the port 8 in the front of the cylinder drives thehammer upwardly or toward the right until said hammer closes the sup-`the port 12, passage 10, and the main exhaustport 13, leading to theatmosphere. At about this period vthe supply-chamber 'is incommunication with the port'14, as indicated'in Fig. 2, by reason of theneck or groove C, and the motiveluid passes through the port 14 andpassage-15 and enters the back or extreme right-hand end of the cylinderthrough the port 16, and the hammer isdriven forcibly and rapidly intocontact with the chisel' or tool 17. I/Vhen the hammer is in theposition indicated in Fig. 2, the exhaust-port 11 is open and permitsall the air to escape from the front end of the cylinder out through theport 12, exhaust passage 10, and main exhaust-port 13 into theatmosphere. When the hammer in its downward stroke closes thesupply-chamber 5, no more air can enter the back or right-hand end ofthe cylinder; but the expansion of the compressed air will drive thehammer downwardly until the latter contacts with the chisel or tool andat about this period opens the exhaust-port 9 again, the parts thenappearing as seen in Fig. 1.

It will be evident that since the hammer in the above-described toolworks only for onequarte'r of its stroke at a direct pressure and theremaining three-quarters of said stroke by expansion the tool uses themotive fluid very economically, and as the inlet-port 8 on the front endof the cylinder is but one-quarter the size of the inlet-port 16 on theback end of the cylinder and since the exhaustport 9 on the back orright-hand end of the cylinder is but one-quarter the size of theexhaust-ports 11 on the front or chisel end of the cylinder the hammerhas a comparatively slow backward movement and a very rapid forwardmovement in the direction of the chisel or tool, thereby striking a veryhard and rapid blow thereupon.

It will be noted that the supply-pipe issecured directly to the cylinderor casing without any extra inlet-piece or other fittings, therebymaking a perfectly air-tight casing under all conditions.

. It will be understood that the terms right and left or front and backend of the tool are merely relative terms, the chisel end of the toolbeing termed the front and the opposite end the back end.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. A pneumatic tool having its inlet-port in the front end of thecylinder, substantially one-quarter the size of the inlet-port on theback end of the cylinder, and the exhaustport on the back end of saidcylinder substantially one-quarter the size of the exhaust-port on thefront or chisel end of the cylinder and all of said ports beingcontrolled by the piston-hammer, whereby a comparatively slow backwardmovement and a very fast forward movement of the hammer are obtained.

2. In a pneumatic tool, a cylinder having a piston-hammer therein, thestriking-face or nose of said hammer being of reduced diameter, achisel-bushing in which said nose has an air-tight fit when the hammeris inits ex- 'treme forward or downward position, an exhaust-portcontrolled by said nose and leading to the atmosphere, said nose beingadapted to be moved out of said bushing and other inlet and exhaustports whereby movement is imparted to said hammer.

3.y In a pneumatic tool, acylinder, a pistonhammer contained therein,said hammer consisting of the grooved portions or necks C, E, the solidportions B, D, F of greater diameter and the nose A of reduced diameter,in combination with inletand Vexhaust ports for admitting and exhaustingthe motive fluid to and from said cylinder, certain of' saidexhaust-ports being controlled by the nose of said hammer.

4. In a-pneumatic tool, a cylinder and a main inlet-port having anenlarged supply-chamber communicating therewith, saidchamber beinglocated within the interior periphery of the cylinder,whereby no sidepressure on the hammer exists, and other inlet and exhaust ports locatedwithin said cylinder, in vcombination with a hammer having a nose ofreduced diameter, said nose being adapted to control certain of saidexhaust-ports.

5. In a pneumatic tool, a cylinder having a chisel-bushing securedtherein, a piston-hammer having a nose adapted to have an airtight fitin said bushing, when said hammer is in its extreme forward position,an'exhaustport passing throughv said bushing, and communicating'with amain exhaust-passage in said cylinder, a main inlety and other inlet andexhaust ports for enabling motion to be imparted to said hammer.

6. A pneumatic tool, consisting of a cylinder having an inlet-port inthe front end thereof, substantially one-quarter the-size of theinlet-port on the back end thereof, and an exhaust-port at the back endthereof substantially one-quarter the size of the exhaustport on thefront or chisel end thereof, and a hammer in said cylinder provided witha reduced nose, the latter being adapted to control 'said exhaust-portat the chisel end of said cylinder.

7. In a pneumatic tool, a cylinder, a piston- IOO IIO

hammer contained therein and provided With a nose of reduced diameter,exhaustports in said cylinder controlled by said nose and' means foractuating said hammer.

8. In a pneumatic tool, a cylinder having a main inlet-port for themotive fluid, an enlarged supply-chamber communicating there- With, andlocated Within the interior periphery of said cylinder, a piston-hammermovable in said cylinder and provided With a reduced nose, achisel-bushing in said cylinder, Which said nose is adapted to enter andan exhaust-port in said bushing controlled by said nose.

9. In a pneumatic tool, the combination of a cylinder having achisel-bushing with an exhaust-port therein, a piston-hammer having anose of reduced diameter controlling said port, and means forreciprocating said hammer.

l0. In a pneumatic tool, the combination l1. In a pneumatic tool, acylinder, a piston-hammer adapted to reciprocate therein,4

said hammer being provided With a projecting striking-face, anexhaust-port in said cylinder controlled by said striking-face and otherports controlled by said hammer for actuating the latter.

HERMAN GEORGE KOTTEN. Witnesses:

GERALD F. BIRD, ARTHUR D. WALKER.

